1. Field of the Invention
This invention relates to a switch, more particularly to a rotary DIP (dual in-line package) switch.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional rotary DIP switch 10, as disclosed in Japanese Publication No. H11-39997, is shown to include a base 11, a plurality of fixed contact terminals 12 connected to the base 11 by insert molding, a contact plate 13 disposed on the base 11 and having a plurality of movable contact terminals 131, a fixed plate 14 disposed above the contact plate 13, a seal ring 15 disposed on the base 11, a rotary member 16 mounted rotatably on the base 11 and pressing against the seal ring 15, and a top cover 17 covering the rotary member 16 and engaging the base 11.
The rotary member 16 has a top face 161 formed with a cross-shaped recess 1611 for receiving a tool (not shown), a bottom face 162 provided with a plurality of press members 164 for pressing appropriate ones of the movable contact terminals 131, and a periphery 163 interconnecting the top and bottom faces 161, 162 and having a wavy-shaped pattern. The top cover 17 has a top plate 172 formed with a through hole 171 to receive and expose the top face 161 of the rotary member 16, two connecting plates 173 extending downwardly and respectively from two opposite ends of the top plate 172 and engaged to the base 11, and two abutment plates 175 extending downwardly and respectively from two other opposite ends of the top plate 172. Each abutment plate 175 has a radial projection 174 abutting against the periphery 163 of the rotary member 16.
Although the conventional rotary DIP switch 10 has the rotary member 16 with the press members 164 that are capable of pressing the desired ones of the movable contact terminals 131 to contact electrically the corresponding ones of the fixed contact terminals 12 so as to produce an output signal, the conventional switch 10 has the following drawbacks:
1. Since the top cover 17 uses the radial projections 174 of the abutment plates 175 to abut against the periphery 163 of the rotary member 16, only a horizontal radial force (Fx) is exerted on the periphery 163 of the rotary member 16. That is, no force is applied to the rotary member 16 which would ensure electrical contact between the movable contact terminals 131 and the corresponding fixed contact terminals 12, and therefore, the quality of the conventional switch 10 is adversely affected.
2. The top cover 17 presses the rotary member 16 with the horizontal radial force (Fx) which is concentrated in a single direction. Although this can permit the radial projections 174 to press stably against the periphery 163 of the rotary member 16, rotation of the rotary member 16 is made difficult.